1. Field of the Invention
The present invention relates to a turn down ratio (TDR) damper, and more particularly, to a TDR damper which may efficiently deliver gas and air while controlling an amount of gas and air supplied to a burner such as a boiler or a water heater.
2. Description of the Related Art
In general, a burner such as a boiler and a water heater used when using cold water and hot water may include an oil boiler, a gas boiler, an electric boiler, and a water heater according to supplied fuel and may be used for various purposes according to an installation condition. Generally, in such burners, in particular, a gas boiler and a water heater, a Bunsen burner or a premixed burner is used to burn gas fuel. Here, a combustion process of the premixed burner is carried out in such a way that gas and air is mixed with the mixture ratio in an optimal combustion condition and then the mixture air (gas+air) is supplied.
In addition, a performance of a burner is evaluated by a Turn Down Ratio (TDR). The TDR is the ‘ratio of the maximum gas consumption to the minimum gas consumption’ in gas burners in which an amount of gas is variably controlled. For example, when the maximum gas consumption is 50,000 kcal/h and the minimum gas consumption is 10,000 kcal/h, the TDR is 5:1.
In a gas boiler and a water, when the TDR increases, convenience in heating and a use of hot water increases. That is, when a burner is operated in a low TDR (that is, the high minimum gas consumption) and low load of heating and hot water, the burner is frequently turned on and off. Accordingly, a temperature deviation increases while controlling and durability of the burner decreases. In order to improve such matter, various methods to increase the TDR of the burner have been developed. One of the methods is disclosed in Korean Patent Publication No. 10-1308936 (hereinafter, referred to as ‘prior art’).
FIG. 1 illustrates moving paths of gas and air in a prior art.
Referring to FIG. 1 and Korean Patent Publication No. 10-1308936, air and gas moves as shown by arrows in FIG. 1 and are mixed in an outlet. Then, the mixed air and gas is delivered to a turbo fan. However, in a structure as in FIG. 1, gas moves in a vertical direction, whereas air moves in a horizontal direction above the gas. Thus, air may prevent an inflow of gas and accordingly, gas is not actually flowed in the burner of FIG. 1.